Sitting-induced Endothelial Dysfunction Is Prevented in Endurance-trained Individuals.

Area of Science:

• Physiology
• Vascular Biology
• Exercise Science

Background:

• Prolonged sitting is known to impair leg endothelial function.
• This impairment is thought to result from reduced blood flow-induced shear stress.
• The protective effect of endurance training against this impairment is not well understood.

Purpose of the Study:

• To investigate if regular endurance training prevents leg endothelial dysfunction induced by prolonged sitting.
• To test the hypothesis that high endurance-trained individuals are protected from sitting-induced endothelial dysfunction.

Main Methods:

• Compared 10 highly endurance-trained cyclists with 9 untrained men.
• Assessed popliteal artery flow-mediated dilation (%FMD) before and after a 3-hour sitting period.
• Measured popliteal artery diameter and blood velocity hourly during sitting.

Main Results:

• Blood flow and shear rate were similarly reduced in both groups during sitting.
• Untrained individuals showed significant impairment in leg %FMD after sitting.
• Endurance-trained individuals did not exhibit significant impairment in %FMD.

Conclusions:

• Leg endothelial dysfunction induced by prolonged sitting can be prevented by regular endurance training.
• Endurance training appears to protect against the negative vascular effects of sedentary behavior.